First they banned their own modern Alternative Service Book after only 20 years in use. Now, the Very Reverend Colin Slee, the Dean of Southwark, has banned the hymn Jerusalem from his cathedral because it is "not in the glory of God" and is too nationalistic.

But surely there is the radiance of divinity in "And was the Holy Lamb of God on England's pleasant pastures seen"?

The pseudo-scholarly clergy don't like that line because they deny the Glastonbury legend about Jesus coming to England with Joseph of Arimathea. This shows a numbskull literal-mindedness.

When I preach the Resurrection on Easter Day, I try to evoke the Lord's appearances around Galilee, and on the walk to Emmaus, as if they had happened in my beloved Yorkshire Dales.

Blake didn't think Jesus came to England, either. He was a poet and his lines are the stuff of imaginative allusion. But imagination is a bit beyond the reach of the polite mechanicals among the modern clergy.

Christians in England are redeemed by Christ, as surely as the first disciples were redeemed by him in Galilee. Blake's magnificent poem is a way of bringing this home to us, building the truth of the experience into our hearts and minds by using homely, national imagery.

The spirit of God breathes all through Jerusalem. Take the fervent line, "Bring me my chariot of fire." It is straight out of the Bible, the ecstatic vision of the prophet Elijah carried up to heaven in the whirlwind (II Kings 2:11). "Nor shall my sword sleep in my hand" is clearly a reference to "the sword of the Spirit which is the word of God" (Ephesians 6:17).

What the modern clergy can't stand is the powerful evocation of England. When they see the word "England" they don't hear the music of ancient Albion. They see patriotism and national pride, which to them are the next worse things to fascism and expansionary imperialism.

But, as Chesterton said, if a man won't love his country, it is difficult to believe he loves anything. Blake's hymn was a prelude to Milton, and he knew that Paradise Lost, the Fall of Man, happens down the Old Kent Road as definitely as anywhere else.

Odd, the trendy clergy's preference for abstractions and internationalism when it was abstracted international communism under Stalin and Mao which slaughtered millions more even than the über-nationalists in the Third Reich.

There is nothing abstract or theoretical about Blake's hymn. He wasn't writing a report for the General Synod. As a poet of genius, he knew that the way to convey spiritual realities is to incarnate them in things: swords, chariots, clouded hills, mountains green.

St Margaret's, "Parliament's church" in Westminster, disapproves of the line about "dark satanic mills" only by misunderstanding it. No English literature scholar imagines for a minute that Blake was referring to the cotton mills and weaving sheds in Lancashire.

One of our finest biblical commentators, Tom Wright, Bishop of Durham, says: "The 'dark satanic mills' were not the cotton mills and steel mills of the new, noisy and smoky industrial revolution. They were the great churches, such as Westminster Abbey and St Paul's Cathedral, which Blake saw as being hopelessly in thrall to the follies of the world, follies he saw all too clearly in the great thinkers of what was already calling itself the Enlightenment.

He faced down the scorn of Voltaire and Rousseau against the deep mysteries of faith. 'You throw the sand against the wind,' he wrote, 'and the wind blows it back again.'?"

Now, at last, we are getting close to understanding this sour prejudice against Jerusalem among so many clergy. For Blake is attacking them - those who, though they promised at ordination to challenge the follies of the age, actually aid and encourage them.

It is the Jerusalem haters who have swallowed whole all the dogmas of Rousseauism and the secular superstitions of the Enlightenment in its most recent form: political-correctness.

If Blake could hear for five minutes these people banging on about their true preoccupations, the follies of the age - anti-racism, gender egalitarianism, compliance, the foreign aid industry and the paranoid fantasy of global warming - he would sing all the more loudly against this lot: "Bring me my bow… bring me my arrows… bring me my sword…"